JP7041130B2 - Method for Producing Solid-Phase Polymerized Poly (Tetramethylene-2,5-Flange Carboxylate) Polymer and Produced Polymer - Google Patents

Description

The present invention relates to a method for producing a solid phase polymerized poly (tetramethylene-2,5-flangecarboxylate) polymer and the produced polymer.

Polymers with 2,5-flange carboxylate groups have been of interest as potential alternatives to similar polyesters with terephthalate moieties. This interest is specifically directed to the use of poly (ethylene-2,5-flange carboxylate) or PEF as a potential alternative to poly (ethylene terephthalate) (PET). Poly (butylene-2,5-flange carboxylate) or poly (tetramethylene-2,5-flange carboxylate), also known as PBF, has the potential to replace poly (butylene terephthalate) (PBT). Has little interest as something.

U.S. Patent Application Publication No. 2014/200578 describes the preparation of PBF polycondensates. This polycondensate is used as a comparative example to show that the behavior of the film is inferior to the behavior of the film containing poly (trimethylen-2,5-flange carboxylate) (PTF) and PEF. Has been done. PBF was prepared by contacting dimethyl 2,5-flange carboxylate with 1,4-butanediol in a molar ratio of 1: 2 in the presence of a catalyst at a temperature of about 80 ° C. Vacuum was then applied to raise the temperature to 230 ° C. and hold for about 3 hours. A polycondensate having a Tg of about 39 ° C and a melting point of about 169 ° C was obtained.

U.S. Patent Application Publication No. 2013/0171397 states that PBF is very suitable for contact with food. This PBF is made from dimethyl 2,5-flange carboxylate or from 2,5-flange carboxylic acid. Problems arose in the production of PBF when dimethyl 2,5-flange carboxylate was used as a starting material in the polymerization. When prepared from dimethyl ester, the ester was contacted with an equimolar amount of 1,4-butanediol and heated in a reactor at 220 ° C. for 7 hours. When the mixture became viscous, methanol was collected in a trap under vacuum. The polymer thus obtained was cooled and dissolved in DMSO. After dissolution, it was precipitated in methanol. A similar method was applied when 2,5-furandicarboxylic acid was used as a starting material. Excess 1,4-butanediol was used (1.5 mol / 1 mol of acid). The starting material was kept at 220-230 ° C. for 10 hours. An additional heating step was applied at 250-260 ° C. for 10 hours. When the reaction mixture became viscous, the water formed was removed by pumping the reactor under vacuum. The viscous polymer was then cooled and dissolved in DMSO. The polymer was then precipitated in methanol. The reported properties of PBF are mass average molecular weight (Mw) of 159,000 (measured by SEC-MALLS), number average molecular weight of 47,750 (Mn), degree of polymerization of 228 (DPn), melting point of 163 ° C. (Tm) and 104 ° C. glass transition temperature (Tg). It is clear that the polydispersity index of the PBF produced is significantly above 3.0, indicating that the polyester is non-uniform and the chain length varies over a wide range of molecular weights.

Neither the method according to US Patent Application Publication No. 2014/0205786 nor the method according to US Patent Application Publication No. 2013/0171397 applies the solid phase polymerization step.

In European Patent No. 1948709, a part of PBF is subjected to a solid phase polymerization step to produce PBF. According to Example 1 of European Patent No. 1948709, 2,5-furandicarboxylic acid and 1,4-butanediol are contacted at a molar ratio of 1: 3 at temperatures of 150 ° C. and 170 ° C. for about 4 hours. I let you. A 5 Pa vacuum was then applied for about 1 hour and the reaction was continued at 180 ° C. for an additional 6.5 hours. The polymer thus obtained was dissolved in hexafluoroisopropanol and reprecipitated with methanol. After drying in vacuum at 60 ° C., the resulting precipitate is subjected to solid phase polymerization at a temperature of 150 ° C. to correspond to a number average molecular weight of 59,850 (measured by GPC using polymethylmethacrylate as a standard). ) A polymer having a degree of polymerization of 285 was obtained. No mass average molecular weight has been reported.

Other than temperature, European Patent No. 1948709 does not mention the conditions under which solid phase polymerization occurs. No mention is made of how long the solid phase polymerization process lasted. Furthermore, this document does not mention what parameters influence the determination of the rate of the solid phase polymerization process.

U.S. Patent Application Publication No. 2014/0205786 U.S. Patent Application Publication No. 2013/0171397 European Patent No. 1948709

When a solid phase polymerization step is carried out using a poly (tetramethylene-2,5-flange carboxylate) having a specific content of carboxyl end groups and subjected to a crystallization step, the solid phase polymerization rate is increased. It has now been found. Therefore, the present invention is a method for producing a solid phase polymerized poly (tetramethylene-2,5-furandicarboxylate) polymer.
-Carboxylic acid end group content up to 50 milliequivalents / kg with a number average molecular weight (Mn) of at least 10,000, as determined by gel permeation chromatography (GPC) using polystyrene as a standard. Step to prepare poly (tetramethylene-2,5-furandicarboxylate) polycondensate to have;
-A step of keeping the poly (tetramethylene-2,5-furandincarboxylate) polycondensation at a temperature in the range of 80 to 140 ° C. to obtain a semi-crystalline polycondensate; and-the semi-crystalline polycondensation. The product is at a temperature of at least 140 ° C., which is lower than the melting point of the semi-crystalline polycondensate, either in the state where the semi-crystalline polycondensate is under an inert gas flow or under vacuum. Provided is a method including a step of subjecting to solid phase polymerization by keeping the temperature at a temperature.

The method of the present invention uses a relatively low molecular weight polycondensate obtained from a polycondensation reaction and having a carboxylic acid terminal group content of up to 50 millie./kg. It was found that when the acid terminal group content was high, solid phase polymerization did not occur under the described conditions, or the solid phase polymerization rate was very slow. This polycondensate tends to be amorphous. By exposing the polycondensate to a temperature in the range of 80 to 140 ° C. for a certain period of time, the amorphous polycondensate crystallizes, which promotes solid phase polymerization. The solid phase polymerization step in the method according to the invention is very effective in that it proceeds at a considerably high rate. In addition, the achievable molecular weight is very high and can exceed 60,000 as determined by gel permeation chromatography (GPC) using polystyrene as a standard. In addition, some prior art methods use a dissolution and precipitation step, in which the polymer produced after the polycondensation reaction of the 2,5-furandicarboxylic acid or its diester is first dissolved and then methanol. Precipitate inside. These steps remove the low molecular weight components in the polycondensation polymer. This means that material loss will occur. Since the method of the present invention does not require a melting step and the melting step can be avoided, such a loss can be avoided by the method of the present invention.

In the first step of the method of the present invention, a poly (tetramethylene-2,5-flangecarboxylate) polycondensate (hereinafter referred to as "PBF polycondensate") is prepared. This PBF polycondensate can be obtained by various methods. The first method is similar to that described in European Patent No. 1948709. In this method, 2,5-furandicarboxylic acid (2,5-FDCA) is mixed with 1,4-butanediol and subjected to an esterification reaction. To ensure that the number of carboxylic acid end groups in the final polycondensate does not exceed 50 eq / kg, the molar ratio of 2,5-FDCA to 1,4-butanediol is appropriately 1. : 1.5 to 1: 5, preferably in the range of 1: 2 to 1: 4. In addition, the water formed during the esterification reaction is removed from the reaction mixture to avoid saponification of the formed esters. In this way, most of the carboxylic acid groups in 2,5-FDCA are esterified before the resulting esterification reaction product is subjected to a polycondensation reaction. The CEG content of the resulting polycondensate can more easily be at levels of less than 50 eq / kg. In the esterification reaction, 2,5-FDCA and 1,4-butanediol are brought into contact with each other in the presence or absence of a catalyst. The esterification reaction is catalyzed by acid groups, and the acid groups are already supplied by 2,5-FDCA, so the presence of a catalyst is not required. The esterification reaction is carried out at a temperature in the range of 150 to 245 ° C, preferably 160 to 245 ° C, more preferably 160 to 190 ° C. At temperatures below 175 ° C, esterification proceeds fairly slowly. Most preferably, the esterification reaction is carried out in the temperature range of 175 to 210 ° C. It has been found that at temperatures above 190 ° C., 1,4-butanediol can react while forming tetrahydrofuran (THF). The formed THF can be easily removed by distillation. Since THF forms an azeotropic mixture with water, water can be easily removed with THF. At temperatures above 175 ° C, water may not be completely removed and saponification may occur. Thereby, the CEG content of the final polycondensate may be increased to a level of more than 50 millivalents / kg. The product of this esterification reaction contains bis (4-hydroxybutyl) -2,5-flange carboxylate. The esterification reaction can be carried out for as long as described in the prior art. It includes that the reaction time can be in the range of 0.5-8 hours, preferably 1-6 hours.

This esterification reaction product is reacted with a polycondensation catalyst under reduced pressure in a polycondensation step. The polycondensation step may be performed in one or more separate steps. The esterification reaction product can be placed under vacuum, for example at a pressure in the range of 0.1-10 millibars. Alternatively, the pressure may be reduced stepwise, for example by a first step at a pressure of 100 to 500 millibars followed by a final vacuum step at a pressure in the range 0.1 to 10 millibars. The temperature in the polycondensation step can be in the range of 180 to 280 ° C. Appropriately, the temperature can be raised in the polycondensation step. The polycondensation reaction preferably lasts for 1 to 6 hours. Excess 1,4-butanediol affects the polycondensate, but the method by which the polycondensation reaction is carried out is not important.

As an alternative to the method described above, the PBF polycondensate can be obtained by transesterification of the dialkyl ester of 2,5-FDCA with 1,4-butanediol. Suitable dialkyl esters include di (C1 _- C6 _- alkyl) esters, especially dimethyl and diethyl esters. The molar ratio of 2,5-FDCA dialkyl ester to 1,4-butanediol is preferably in the range of 1: 1.1 to 1: 2.5, preferably 1: 1.3 to 1: 2.0. Is. The transesterification reaction is properly carried out in the presence of a transesterification catalyst. In the transesterification step, the alkyl group is replaced by a 4-hydroxybutyl group. Appropriately, the alkyl alcohol formed accordingly is removed from the reaction mixture. The temperature at which the transesterification reaction is carried out can preferably be in the range of 150 to 250 ° C, preferably 160 to 240 ° C. The risk of THF formation is minimal as only a slight excess of 1,4-butanediol is used in the transesterification reaction. Therefore, the reaction temperature during the transesterification reaction is preferably at least 200 ° C, more preferably 205 to 235 ° C. The transesterification reaction can be carried out for a period of time as described in the prior art. It includes that the transesterification reaction time can range from 0.5 to 6 hours, preferably 1 to 4 hours. The polycondensation reaction can be carried out as described above for the esterification reaction product from 2,5-FDCA and 1,4-butanediol. In this regard, it has been observed that since the starting material does not contain carboxylic acid end groups, the resulting polycondensate has a low carboxylic acid end group content, eg less than 50 milliequivalents / kg.

Carboxylic acid end groups are determined by using an ASTM D7409 compliant titration method adapted to poly (tetramethylene-2,5-furandicarboxylate). The modified method uses 0.01 M KOH in ethanol as a titrator of a 4% (mass / volume) solution of poly (tetramethylene-2,5-furandicarboxylate) in ortho-cresol. Titration to that equivalence point, 0.5 mg of bromocresol green in 0.1 mL of ethanol as an indicator [2,6-dibromo-4- [7- (3,5-dibromo-4-hydroxy-2) -Methyl-phenyl) -9,9-dioxo-8-oxa-9λ6-thiabicyclo [4.3.0] nona-1,3,5-triene-7-yl] -3-methyl-phenol] titration including.

A polycondensate produced by the reaction of 2,5-FDCA with 1,4-butanediol or by the transesterification reaction of a dialkyl ester of 2,5-FDCA with 1,4-butanediol was produced. It is observed that it is appropriate to use as is directly, i.e. without subjecting to the dissolution and precipitation steps, to provide to the next step of the method according to the invention. Therefore, the poly (tetramethylene-2,5-furandicarboxylate) polycondensate to be subjected to the step of keeping the temperature at 80 to 140 ° C. is from the esterification using 1,4-butanediol of 2,5-FDCA. Alternatively, it is appropriately produced from a transesterification reaction of a dialkyl ester of 2,5-FDCA without being subjected to a dissolution step and a precipitation step.

The transesterification catalysts that can be used in the transesterification reactions described above include metal oxides, salts and organic metal compounds. Suitable salts include carbonates, halides and carboxylates such as formates, acetates, propionates, butyrates, benzoates, and mixtures thereof. Salts of carboxylic acids having long carbon chains, such as carbon chains such as 6 to 20 carbon atoms, can also be used. Examples of such carboxylic acids are lauric acid, stearic acid, octanoic acid, such as 2-ethyl-hexanoic acid. Suitable organometallic compounds include alcoholates such as C1- _{C4 -} alkoxides and glycolates such as ethylene glycolates and glycolates having 1 to 4 methylene groups. The other organometallic compound is an alkyl metal carboxylate, where the alkyl moiety is selected from C ₁ to C ₆ alkyl groups and the carboxylate is derived from a C ₁ to C ₂₀ carboxylic acid. The metal is appropriately selected from zinc, lead, tin, titanium, hafnium, zirconium, calcium, magnesium, strontium and combinations thereof. Although no esterification reaction catalyst is required, the transesterification reaction catalyst described above can be used in the esterification reaction of 2,5-FDCA and 1,4-butanediol.

Many transesterification reaction catalysts can be used as the polycondensation reaction catalyst. Suitable polycondensation reaction catalysts include one or more elements selected from tin, titanium, zinc, antimony, calcium, manganese, cobalt, hafnium, lead, magnesium, aluminum, cerium, zirconium, and mixtures thereof. Includes catalysts. These compounds may be acetates or carbonates of these metals. Alternatively, it may be a metal alkoxide, an alkyl metal compound, or another organometallic compound. Other suitable catalysts include oxides and halides of the elements mentioned above. Preferred catalysts include titanium alkoxide, antimony acetate, antimony oxide, and antimony glycolate, such as the reaction product of antimony oxide and ethylene glycol. The amount of polycondensation reaction catalyst is calculated as metal and is typically in the range of 0.005 mol% to 0.2 mol%, preferably in the range of 0.005 mol% to 0.2 mol%, based on the number of moles of 2,5-furandicarboxylic acid in the starting mixture. Is in the range of 0.01 to 0.15 mol%. When transition metals are used, some metals appear to function differently at one valence than at another. For example, tin (IV) salts tend to result in more colorless polymers than tin (II) salts, whereas tin (II) salts are solid phase polymerized polymers with higher molecular weight than tin (IV) salts. Tends to bring. Preferred transesterification and polycondensation reaction catalysts include zinc acetate, zirconium (IV) butoxide, titanium (IV) butoxide, tin (II) (2-ethylhexanoate), tin (II) acetate, butyltin (IV). Includes tris (2-ethylhexanoate), dibutyltin (IV) dilaurate, and tributyltin (IV) benzoate.

According to the present invention, the poly (tetramethylene-2,5-flangecarboxylate) polycondensate is:
(i) A method in which a dialkyl 2,5-furandicarboxylate and 1,4-butanediol are subjected to a transesterification reaction to obtain a transesterification reaction product, and then the transesterification reaction product is polycondensed;
(ii) Select from the group consisting of a method of subjecting 2,5-furandicarboxylic acid and 1,4-butanediol to an esterification reaction to obtain an esterification reaction product, and then polycondensing the esterification reaction product. It is clear that one of the methods used is adequately obtained.
Therefore, the present invention is a method for producing a solid phase polymerized poly (tetramethylene-2,5-furandicarboxylate) polymer.
-Poly (tetramethylene-2,5-flange carboxylate) polycondensate,
(i) A method in which a dialkyl 2,5-furandicarboxylate and 1,4-butanediol are subjected to a transesterification reaction to obtain a transesterification reaction product, and then the transesterification reaction product is polycondensed;
(ii) Select from the group consisting of a method consisting of an esterification reaction of 2,5-furandicarboxylic acid and 1,4-butanediol to obtain an esterification reaction product, and then polycondensation of the esterification reaction product. The poly (tetramethylene-2,5-furandicarboxylate) polycondensate is determined by gel permeation chromatography (GPC) using polystyrene as a standard in the step of preparation by one of the methods. The step of carrying out the polycondensation reaction so as to have a number average molecular weight (Mn) of at least 10,000 and a carboxylic acid terminal group content of up to 50 milliequivalents / kg;
-A step of keeping the poly (tetramethylene-2,5-furandincarboxylate) polycondensation at a temperature in the range of 80 to 140 ° C. to obtain a semi-crystalline polycondensate; and-the semi-crystalline polycondensation. Solid phase polymerization of the product by keeping the semicrystalline polycondensate at a temperature of at least 140 ° C. and lower than its melting point, either under an inert gas flow or under vacuum. Also provided are methods that include the step of subjecting.

As pointed out above, the content of carboxyl end groups (CEGs) in the polycondensate is by using a dialkyl ester of 2,5-FDCA as a starting material for the transesterification reaction and subsequent polycondensation reactions. , It can be relatively easily reduced to a value of less than 50 mm equivalent / kg. Thus, the polycondensation reaction typically results in a polycondensate with a carboxylic acid end group content of less than 50 millie./kg. When 2,5-FDCA is used as the starting material for the esterification reaction, the CEG content in the resulting polycondensate can exceed 50 milliequivalents / kg. The CEG content is affected by increasing the relative amount of 1,4-butanediol and / or by removing the water formed during the esterification reaction of FDCA with 1,4-butanediol. obtain. In the method of the present invention, it has been found advantageous to have a relatively low CEG content value. Good results are obtained when the PBF polycondensate has a CEG content in the range of 1-50 eq / kg. It is noteworthy that for PBF polycondensates, it is advantageous to have a low CEG content. According to WO 2015/137807, the CEG content in the poly (ethylene-2,5-flange carboxylate) (PEF) polycondensate should not be too low to obtain a relatively fast solid phase polymerization. It is described as. The CEG content in the PEF polycondensate is preferably 15-122 milliequivalents / kg. The CEG content in the PBF polycondensate may be low, for example, in the range of 1-25 millivalents / kg, preferably 1-15 millivalents / kg, more preferably 2-14 millivalents / kg. .. Surprisingly, with such a low CEG content, the solid phase polymerization reaction is optimized both in terms of polymerization rate and achievable molecular weight.

Poly (tetramethylene-2,5-flangecarboxylate) polycondensates have a number average molecular weight (Mn) of at least 10,000 as determined by gel permeation chromatography (GPC) using polystyrene as a standard. In this regard, it is observed that the determination of Mn by GPC using polystyrene as a standard results in different values than the determination of Mn by GPC using polymethylmethacrylate (PMMA) as a standard.

The method of the present invention is a poly (tetramethylene-2,5-) having a Mn in the range of 10,000 to 35,000, preferably 12,000 to 30,000, as measured by GPC using polystyrene as a standard. Frangicarboxylate) Appropriately carried out with polycondensate.

It was found that when the poly (tetramethylene-2,5-furandicarboxylate) polycondensate was kept at a temperature in the range of 80 to 140 ° C., solid phase polymerization proceeded smoothly and a semicrystalline polycondensate was obtained. It was issued. During this heating step, the chains in the polycondensate are rearranged to form a semi-crystalline polymer. Preferably, the poly (tetramethylene-2,5-flangecarboxylate) polycondensate is held at a temperature in the range of 80-130 ° C. for a time in the range of 0.5-4 hours. The poly (tetramethylene-2,5-flangecarboxylate) polycondensate is appropriately kept in ambient conditions. This means that the pressure is not increased or decreased. No special measures need to be taken regarding the inactivation of the atmosphere. The atmosphere during this process may be air. No artificial air or inert gas flow is required. Such a flow is not properly implemented. The crystallinity of the polymer can be determined using a differential scanning calorimetry (DSC) by quantifying the heat associated with the melting of the polymer. The heat can be reported as a percentage of crystallinity by normalizing the heat of fusion to the heat of fusion of a 100% crystalline sample. However, 100% crystalline samples are rare. Therefore, crystallinity is often expressed as a net enthalpy in units of joules per gram, the number of which is derived from DSC technology. The enthalpy of melting and crystallization can be determined in accordance with ISO 11357-3. The polycondensate used in the method according to the present invention is preferably 25 to 75 J / g, preferably 30 to 65 J / g, as measured by differential scanning calorimetry (DSC) by the formed semicrystalline polycondensate. It is kept in the temperature range described above for a period of time such that it has a degree of crystallinity.

Semi-crystalline polycondensates with a certain degree of crystallinity also have a melting point Tm. The melting point of the polymer is easily detected by DSC and measured at the apex of the endothermic peak. For the purposes of the present invention, the terms "melting point" and "Tm" refer to the temperature measured at the peak at ISO-11357-3 called Tpm. If the DSC shows multiple peaks, the melting point or Tm refers to the Tpm of the peak at the highest temperature. The ISO 11357-3 standard describes such a melting point determination. According to this measurement, the semi-crystalline polycondensate preferably has a melting point in the range of 165 to 175 ° C. as measured by differential scanning calorimetry (DSC). During the method of the present invention, it has been observed that the melting point and crystallinity of the polycondensate increase.

The semi-crystalline polycondensate thus obtained is subsequently subjected to a solid phase polymerization reaction. To this end, the semi-crystalline polycondensate is kept at a temperature of at least 140 ° C. below its melting point, during which the semi-crystalline polycondensate is placed under an inert gas flow or vacuum. Preferably, the semi-crystalline polycondensate is kept at a temperature 5-30 ° C. below its melting point during solid phase polymerization. Typically, it is required to keep the semicrystalline polycondensate at a temperature in the range of 145 to 165 ° C. during solid phase polymerization. In one embodiment, the semicrystalline polycondensate is heated in vacuum while maintaining a pressure level of, for example, 0.001 to 0.2 millibar. In another preferred embodiment, the semi-crystalline polycondensate is heated while passing an inert gas along the semi-crystalline polycondensate during the solid phase polymerization reaction. The inert gas is appropriately selected from nitrogen, helium, argon, neon, carbon dioxide, and mixtures thereof. The inert gas is adequately virtually free of water vapor. Preferably, the inert gas stream is used because the use of the inert gas stream typically favors more effective removal of by-products than the use of vacuum. In particular, tetrahydrofurans that may form from butanediol residues and cyclic oligomers that may form white dust or fine particles in melt-processed articles or in instruments used for melt processing are non-existent. It is removed more effectively by the use of an active gas stream.

The rate at which the molecular weight increases during this solid phase polymerization reaction step is very advantageous in order to obtain the semi-crystalline polycondensate and its specified range of carboxyl end groups. That means that, depending on the desired final molecular weight, solid phase polymerization can be extended as long as one of ordinary skill in the art deems it desirable. Typically, the semi-crystalline polycondensate is kept at a temperature below its melting point for a period of 2 to 120 hours, preferably 12 to 96 hours, during solid phase polymerization.

The solid phase polymer obtained by the method according to the present invention was found to be very transparent and colorless. It is noteworthy that the polymer obtained by the method according to European Patent No. 1948709 is stated to have a light transmittance of 85%. Therefore, these prior art polymers have a haze of 6.5% (both haze and light transmittance are determined according to JIS K 7105, which is equivalent to ASTM D1003). Relationship between Absorbance and Light Transmittance: According to Absorbance = -log (percent transmittance / 100), the absorbance of the polymer of European Patent No. 1948709 appears to be about 0.07.

Polymers prepared using the method according to the invention were subjected to absorbance measurements at a wavelength of 400 nm at a concentration of 30 mg / mL in a mixture of dichloromethane and hexafluoroisopropanol in an 8: 2 volume / volume ratio. These polymers exhibit improved optical properties, as shown by the absorbance compared to prior art polymers. European Patent No. 1948709 also does not indicate what measures can be applied to improve the absorbance. Therefore, it is surprising that PBF polymers made according to the present invention have this advantageous property.

Accordingly, the present invention has a melting point in the range of 168 to 175 ° C. and has a number average molecular weight (Mn) of at least 40,000 as determined by gel permeation chromatography (GPC) using polystyrene as a standard. Also provided are poly (tetramethylene-2,5-furandicarboxylate) polymers having an absorbance of up to 0.05 as measured as described above. It is even more surprising that these polymers have a polydispersity index of up to 3.0, preferably 1.9 to 2.6, more preferably 2.0 to 2.45. This indicates that the polymer produced is more uniform than the PBF produced in accordance with US Patent Application Publication No. 2013/0171397. Nevertheless, the mass average molecular weight (Mw) of the polymer according to the invention can be rather high. A value of Mw in excess of 135,000 can be achieved relatively easily. Suitably, the Mw of the polymers according to the invention are all measured by GPC using polystyrene as a standard, 100,000 to 250,000, preferably 100,000 to 200,000, more preferably 120,000. It is in the range of ~ 175,000.

The polymer can conveniently have a number average molecular weight in the range of at least 45,000, preferably 45,000 to 80,000. The number average molecular weight can be adjusted by prolonging the solid phase polymerization.

Absorbance can be very low. Its value may be influenced to some extent by the catalyst used in the polycondensation reaction and / or the solid phase polymerization reaction. The absorbance is preferably in the range of 0.001 to 0.04.

The degree of crystallinity of the polymer may be appropriately in the range of 30 to 85 J / g, preferably 35 to 65 J / g, as measured by DSC.

The polymer thus obtained has excellent mechanical properties. The polymer can be spun into fibers with excellent tenacity. The monofilament can be spun and the as-spun monofilament can be stretched in one or more drawing steps, eg, using hot pins, to a ratio in the range of 2-10, preferably 3-8. This monofilament has excellent tenacity. Tenacity in the range of 250-500 mN / tex, preferably 300-400 mN / tex, can be achieved. The break point elongation can be in the range of 15-50%, for example 20-45%. The crystallinity of the polymer in the fiber can be in the range of 30-70 J / g. The birefringence of the drawn fiber is higher than that of the as-spun fiber. For example, if the fiber is spun with a diameter of 196 μm, it may have a birefringence (Δn) of 0.0016. When stretched at a stretch ratio of 4, it may have a diameter of 104 μm and a birefringence of 0.1433. Birefringence increased to 0.1237 when stretched at a stretch ratio of 2. This indicates that fibers made from the polymers according to the invention can have birefringence in the range 0.2-0.001 depending on the draw ratio.

The obtained polymer also has excellent gas barrier properties. Therefore, they are very suitable for use as packaging materials such as films or containers such as bottles. The polymer has a glass transition temperature in the range of 35-45 ° C. In non-oriented films, the polymer has better gas barrier properties than, for example, polybutylene terephthalate (PBT). The polymer has an oxygen permeability of ml (STP), mil (thousandth of an inch) / 100 square inches, day, and atmospheric pressure at 23 ° C and 50% relative humidity compared to 6-7 of PBT. , 1.6. The water permeability is almost the same for the polymers and PBTs of the present invention. At 38 ° C. and 100% relative humidity, at 1.5 g · mil / 100 square inches · day · atm compared to 1.3 g · mil / 100 square inches · day · atm for the polymer according to the invention. be. The CO ₂ transmittance is about 5.2 ml (STP) mil / 100 square inches / day / atmospheric pressure at 23 ° C. and 0% relative humidity. Due to the excellent mechanical properties of the polymer and the excellent transparency, the polymer is very suitable for packaging, such as bottles and films.

The method and polymers have been described with reference to poly (tetramethylene-2,5-flangecarboxylate) polymers. This polymer may consist essentially of only 2,5-flange carboxylate groups and tetramethylene moieties. However, for the purposes of this application, the polymer contains a small amount, eg, up to 10 mol%, preferably up to 5 mol% of one or more other dicarboxylic acid groups and diol moieties. You may be. Suitable dicarboxylic acid groups include terephthalic acid, isophthalic acid, phthalic acid, adipic acid, 2,4-furandicarboxylic acid, naphthalenedicarboxylic acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid, and Includes residues of their mixture. Suitable diols include ethylene glycol, 1,3-propanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, isosorbide. However, it is preferred that the poly (tetramethylene-2,5-flangecarboxylate) polymer comprises substantially 2,5-flange carboxylate and a tetramethylene moiety.

The present invention will be described with reference to the following examples.

[General procedure]
13.8 g (75 mmol) of dimethylfuran carboxylate (DMF) and 12.8 g of 1,4-butanediol were introduced into a 100 mL container. This means that the molar ratio of 1,4-BD: DMF is 1.9. Specific amounts of transesterification reaction and polycondensation reaction catalysts were also added.

The resulting mixture was heated in an oil bath heated to the transesterification reaction temperature. The transesterification reaction temperature was 215 ° C. Methanol began to distill and was removed. When substantially all the methyl groups were replaced with hydroxybutyl groups, a vacuum was applied to the vessel and the temperature of the vessel was raised to about 225 ° C. to initiate the polycondensation reaction. Unless otherwise indicated, the polycondensation reaction was continued for 2.5 hours. The resulting polycondensate was cooled to a solid, pulverized and sieved.

The polycondensation particles were heated at 110 ° C. for 2 hours for crystallization to give a semi-crystalline polycondensate.

After crystallization, the semi-crystalline polycondensate is subjected to solid phase polymerization by holding the semi-crystalline polycondensate under a nitrogen flow of 4 mL / min (mL amount is measured at standard temperature and pressure) and at a temperature of 150 ° C. rice field. The number average molecular weight was measured at various time intervals of the solid phase polymerization reaction.

[Example 1]
Titanium (IV) butoxide as a catalyst was calculated as a metal based on the amount of DMF and used in an amount of 0.02, 0.03, or 0.04 mol%, using the general procedure described above 4 Two tests were performed. The transesterification reaction was continued for 4 hours. Then, the polycondensation reaction was started and continued for the number of hours shown below. The polycondensation reaction temperature was 240 or 225 ° C. The CEG content and molecular weight of the polycondensate (Mn and Mw, measured by CEG using polystyrene as a standard) were measured. The polycondensate was subjected to solid phase polymerization (SSP) as described in the general procedure. Mw'and Mn' of the solid phase polymer were measured after various times of solid phase polymerization. The polydispersity index (PDI) was calculated as Mw / Mn. The absorbance of the solid polymer [measured with a sample at a concentration of 30 mg / mL in a mixture of dichloromethane: hexafluoroisopropanol 8: 2 (volume / volume) at 400 nm] was also measured using a Heliosα (ThermoSpectronic) spectrophotometer. did.

The reaction conditions and results are shown in Table 1.

Test number 1 is a comparative test. It has a CEG content after polycondensation reaction greater than 50 milliequivalent / kg. Other tests have a CEG content of less than 50 eq / kg. A comparison of the results of test numbers 2-4 with the results of comparative test numbers 1 shows that the rate at which SSPs occur is much higher and results in higher molecular weight.

These results indicate that the absorbance of the polymers of Test Nos. 2-4 is lower than that of the polymers of Comparative Test No. 1.

[Example 2]
In order to show the influence of the polycondensation reaction temperature, the test was generally performed according to the above-mentioned test number 4. The transesterification reaction time in each test was 4 hours. The polycondensation temperature was changed. It was found that increasing the temperature not only increased the polycondensation reaction rate, but also increased the CEG content. The polycondensation reaction time was adjusted so that the CEG content did not exceed an appropriate limit. The conditions and results are shown in Table 2 below.

[Example 3]
Five further tests were performed to demonstrate the performance of tin-containing transesterification and polycondensation reaction catalysts. The reaction conditions were generally as described in the general procedure. The catalysts used were butyltin (IV) tris (2-ethylhexanoate) (“catalyst 1”), dibutyltin (IV) dilaurate (“catalyst 2”), tributyltin (IV) benzoate (“catalyst 3”), tin. (II) (2-ethylhexanoate) (“catalyst 4”), and tin (II) acetate (“catalyst 5”). The reaction conditions and results are shown in Table 3.

[Example 4]
In a series of tests, 2,5-FDCA was calculated based on the molar amount of 2,5-FDCA as a metal and 1,4-butanediol in the presence of 0.04 mol% titanium (IV) butoxide. It was polymerized with (1,4-BD). 2,5-FDCA was mixed with a certain amount of 1,4-butanediol and a catalyst at 175 ° C. As a result, a slurry of solid 2,5-FDCA in 1,4-butanediol was obtained. Water was generated and removed. When the mixture became clear after about 4 hours, the mixture was slowly heated for an additional 3 hours and kept at the esterification reaction temperature of 205 ° C. for 1 hour. The polycondensation reaction was carried out at 225 ° C. for 2.5 hours as described in the general procedure. The polycondensate thus obtained was cooled, solidified, pulverized and sieved.

The polycondensation particles were heated at 110 ° C. for 2 hours for crystallization to give a semi-crystalline polycondensate.

After crystallization, the semi-crystalline polycondensate was kept at a temperature of 150 ° C. under a nitrogen flow of 4 mL / min to achieve solid phase polymerization.

The CEG content and Mn of the polycondensate were measured. Mn'at various stages of solid phase polymerization was also measured. Finally, the absorbance of the solid phase polymer was measured as described above. The PDI of the polycondensate and the solid phase polymerized polyester was less than 3.0 in both tests.

Other reaction conditions and results are shown in Table 4.

Test number 14 is a comparative test, where the polycondensate has a CEG content of greater than 50. These results indicate that the SSP method of test number 13 yields a faster increase in molecular weight, a higher final molecular weight and a lower absorbance than the SSP method of test number 14. ing.

Claims (14)

A method for producing a solid phase polymerized poly (tetramethylene-2,5-flangecarboxylate) polymer.
-With a number average molecular weight (Mn) in the range of 10,000 to 35,000 , determined by gel permeation chromatography (GPC) using polystyrene as a standard, in the range of 1 to 50 milliequivalents / kg. A step of preparing a poly (tetramethylene-2,5-furandicarboxylate) polycondensate having a carboxylic acid terminal group content;
-A step of keeping the poly (tetramethylene-2,5-furandincarboxylate) polycondensation at a temperature in the range of 80 to 140 ° C. to obtain a semi-crystalline polycondensate; and-the semi-crystalline polycondensation. The product is at a temperature of at least 140 ° C., which is lower than the melting point of the semi-crystalline polycondensate, either in the state where the semi-crystalline polycondensate is under an inert gas flow or under vacuum. A method comprising the step of subjecting to solid phase polymerization by keeping it at a temperature. The method of claim 1, wherein the poly (tetramethylene-2,5-furandicarboxylate) polycondensate has a carboxylic acid end group content in the range of 1-15 milliequivalents / kg. The method according to claim 1 or 2 , wherein the poly (tetramethylene-2,5-flangecarboxylate) polycondensate has a Mn in the range of 12,000 to 30,000. The poly (tetramethylene-2,5-flangecarboxylate) polycondensate is
(i) A method in which a dialkyl 2,5-furandicarboxylate and 1,4-butanediol are subjected to a transesterification reaction to obtain a transesterification reaction product, and then the transesterification reaction product is polycondensed;
(ii) Select from the group consisting of a method of subjecting 2,5-furandicarboxylic acid and 1,4-butanediol to an esterification reaction to obtain an esterification reaction product, and then polycondensing the esterification reaction product. The method according to any one of claims 1 to 3 , which is obtained from one of the methods. Any one of claims 1 to 4 , wherein the poly (tetramethylene-2,5-flangecarboxylate) polycondensate is kept at a temperature in the range of 80 to 130 ° C. for a time in the range of 0.5 to 4 hours. The method described in the section. The method according to any one of claims 1 to 5 , wherein the semi-crystalline polycondensate has a crystallinity in the range of 25 to 65 J / g as measured by differential scanning calorimetry (DSC). .. The method according to any one of claims 1 to 6 , wherein the semicrystalline polycondensate is kept at a temperature 5 to 30 ° C. lower than its melting point during solid phase polymerization. The method according to any one of claims 1 to 7 , wherein the semicrystalline polycondensate is kept at a temperature in the range of 145 to 165 ° C. during solid phase polymerization. The method according to any one of claims 1 to 8 , wherein the semicrystalline polycondensate is kept at a temperature lower than its melting point for 2 to 120 hours. It has a melting point in the range of 168 to 175 ° C. and a number average molecular weight (Mn) in the range of 40,000 to 80,000 as determined by gel permeation chromatography (GPC) using polystyrene as a standard.
Poly (tetramethylene-) having an absorbance in the range of 0.001 to 0.05 as measured at a wavelength of 400 nm at a concentration of 30 mg / mL in a mixture of dichloromethane and hexafluoroisopropanol in an 8: 2 volume / volume ratio. 2,5-Flange carboxylate) polymer. The poly (tetramethylene- 2,5 -flange) according to claim 10, which is determined by gel permeation chromatography (GPC) using polystyrene as a standard and has a Mn in the range of 45,000 to 80,000. Carboxylate) polymer. 1 . The poly (tetramethylene-2,5- furandicarboxylate ) polymer according to claim 10 or 11, which has a PDI of 9 to 2.6. The poly (tetramethylene-2,5- flangecarboxylate ) polymer according to any one of claims 10 to 12, which has an absorbance in the range of 0.001 to 0.04. The poly (tetramethylene- 2,5 - flange) according to any one of claims 10 to 13, which has a crystallinity of 30 to 85 J / g as measured by differential scanning calorimetry (DSC). Carboxylate) polymer.